Pastes are abrasive and are designed to refresh a dulling edge. Providing that your edge is honed and shave ready (which new ones almost never are) you should use the linen and the leather sides without any sort of paste at all. Normally you only need to hone linen first, then leather, usually 30 times up and down on each side before shaving, then possibly afterwards too depending on your personal preference.

Normally the pros recommend pasting bench strops only - not hanging ones - as a pasted hanging strop is a very hard thing to use. Depending on what paste you have, and how expensive they were, you might be better off getting a pre-pasted bench strop (Tony Miller on this site makes some great ones).

What colours are the pastes?

Cheers

Si