How do i add a texture pack in so that it changes all of the blocks and not just cobblestone, dirt and mobs?
Yes but here is the version for agrarian: [128x/64x/32x] Sphax Texture Pack - FTB AGRARIAN SKIES | MineYourMind Community
i dont understand how to install it :/[DOUBLEPOST=1407416580,1407416288][/DOUBLEPOST] i have the patch and the texture pack downloaded but i dont understand what to do in 7zip?
Read the instruction in the topic. You just need to move all the folders from the patch to the orginal sphax texture pack. You can also look here the yogscast complete pack : Patches - Requests - Page 4 and use the agrarian patch instead of the yogcast.
Open the sphax texture pack folder, the click assets, now open the patch and click assets. Drag the patch assets into the sphax assets. Then put it in the .mineyourmind if you are using mym launcher, or .feedthebeast if you use the FTB launcher.