Can i keep some steam games on a HDD and other on a SSD?

Im wondering if i can install some games like FTL on a HDD and games with a arger file size on a SSD

yes there is an option where to download the game to, make sure to create a new steam library under the ssd and save it there

so like a seprate SteamApps located on my SSD?

If you go to the settings, there is a tab 'Downloads' with a button named 'Steam Library Folders,' click it and everything will be fine.