How to make custom skies

I've been trying for the past few weeks to add a custom sky to Doom 2 but to no success. I want to know how to add a custom sky to doom. I've tried looking for relevant tutorials but they don't seem to work/are too vague to understand. I already have my chosen sky/skies (with the creators confirming that they work once fully added in). Currently using Slade and Doom Builder 2.

Going by this tutorial, the easiest way to make a sky is to get an image that is:

256x128 resolution
make sure it's in "Graphics (Doom)" format - you do that by right clicking - graphics - convert to - GFX palletised
and named RSKY1, if your map is in MAP01 slot or anywhere in the first episode.

That's in the pwad file with your map. And that's it. Here's a little example you can open in SLADE and see how it works.

sky.wad.zip

Depending what you want to do but probably the easiest way could be either to replace RSKY1, RSKY2 or RSKY3 patches with your custom sky textures, taking into account that they need to be 256 units wide by 128 units height and also in Doom graphic format 

or

MBF Sky Transfer:

https://mfg38.github.io/tutorials/mbf-sky-transfer.html#:~:text=How the MBF sky transfer works in its,texture to all untagged sectors with the F_SKY1

This last method you can use any patch of any dimensions.

yup it works now thanks guys!