there are a lot of items that i want to bring over from sims 2 and 4, but i don't know where i'd even begin, im not the best with this kind of stuff but if there's a good starting point i may be able to try it

Converting and making objects in general are nearly identical processes, just with the added step of extracting meshes/textures from the original game and potentially converting them into more suitable formats first.
You could get started using any tutorial as your base. You will also need SimPE to pull things from TS2, and Sims4Studio for TS4.

What kind of items are you looking into converting?

a few outfits and a skin?

Thornowl's tutorial (and the tutorial linked, as well as Lyralei's comments in that thread) are a good place to start with clothing CC.

For skins there is the Skininator, but I'm not sure how easy it is to fit a texture from the other games onto the TS3 body. That would involve a bit more texturing / UV work than a standard conversion.

There are more CAS tutorials here: https://modthesims.info/wiki.php?ti...ENCAS_Tutorials that cover a lot of topics, but some may be quite outdated with the programs they reference. Tumblr is a good place to look for more recent posts about certain types of CC.

i am so lost with these, i'll keep reading and see if i can figure it out

I do not know about TS2, but converting TS4 skins to TS3 is extremely difficult, at best. TS4 uses a completely different UV set up than TS3. Basically, absolutely not a single body part aligns on the textures. As for garments, it can be done, and there are several tutorials out there.

TS4 uses color swatches instead of an rbg(a) mask. Making a swatch into gray scale is simple enough, but making a mask can be a PITA. Many who do conversions do not bother. Generally, exposed skin may be used from a TS3 model, such as hands and neck, so they align better with TS3 rigs and skin textures.

i give the heck up, ive downloaded so many programs and follwoed so many tutorials but i can't make it work,

If you have one project in mind that you would like to start with, you may be able to get advice here for each step you have trouble with.
We can't do it for you, but always feel free to take your time and post screenshots or project files for others to help with

If you link one of the items you'd like to convert, I'd happily give you a list of steps I would personally follow to convert it. It can definitely be a difficult thing to learn from scratch though! It's not really a skill that can be rushed.

As @CardinalSims said, pick one thing to work on first. And no, it is not that easy. You must really want it. Programs I use are s4pe, to extract geoms and textures, S4CASTools, to convert TS4 geoms to object, Blender 2.80, to work mesh and UV, Meshing Tool Kit, to convert object to TS3 geom, add bones, to TSRW .wso, GIMP, to work with textures and resize, and TSRW to put it all together.

I would suggest a closed bottom skirt, or possibly pants, as the easier first options.

i was trying to convert this cc here https://sims-life-in-brunei.blogspo...-sims-2_46.html

i found the mesh in sims 2 that it uses and managed to extract both it and a random clothes mesh that was kinda similar looking from world adventures, but even after trying with both blender and milkspace 3d i just cannot manage to fix the mesh for 3

Sorry, I can't help you with TS2 to 3. I had the tools, used them once and was not worth the effort to continue learning to use them. Do not even think I have them on this laptop. I might be able to help you with 4 to 3. I've done a few of those.

Maybe the shoes would be a good place to start? I'm assuming they're part of the outfit itself as TS2 didn't have separate shoes. Your first practice could be separating the shoes and converting them for TS3

If you're totally new to CAS work in Blender, I have a tutorial for prep and useful tools here.
For starters, you'll want to import the TS2 mesh into Blender and remove any parts you won't need in TS3. You can select the shoe pieces in Edit Mode and right click > Separate.
If you want to prepare the outfit as well, you'll want to remove any TS2 body parts that are attached to it. When you're left with just the clothing you need, you can import the TS3 body mesh(es) as reference for resizing / fitting.

You might want to look at a TS3 cloned item as reference for how the textures are laid out, once you're pleased with the mesh. I think TS3 clothes share a texture map with the body, but I'm not so familiar with that yet so hopefully one of those tutorials covers textures? They'll also need to be a square resolution and in .dds format, which you can do in GIMP or Photoshop.

When the mesh and texture are ready, you have a couple of different methods you can use to get it into a TS3 package.
If you export the mesh as Wavefront Object (.obj), you can do as LadySmoks said from the MeshingToolKit part onwards and assemble with TSRW.
Alternatively, Lyralei's method from this comment you can do it with GEOMs and S3PE.

Experiment and feel free to post screenshots of anything you struggle to get working.

i got about this far and now i dunno what to do, i can't get the texture to appear on the item so im kinda flying blind on how it should look

The locations / appearance of the buttons might vary in the 3+ versions of Blender, but if you skip to the Add Material Properties header in this tutorial you may be able to find the equivalent option to preview your textures. The 'Alpha' part can be ignored if you don't need to see transparency.