You basically have 2 choices on how to do what you want.
1. Install a "MOD" created for the game that lets you play most (if not all) of the "scenes" available in the game. That way you can "cheat" and view the scenes for all the different paths while playing whatever path you want to. The MOD in most cases will also let you do a lot of other things too (like "cheat").
2. Learn how to create "path saves" during your game play. This one may be harder for you to do, as I'm assuming due to the low number of posts you've made you are relatively "new" to playing Renpy games and how they "work" and can allow you to save multiple "paths" in the game WHILE playing the game. Without having "multiple paths" saved (or a MOD installed), there will be only ONE series of "saved data" the game uses to let you do things based on your previous choices.
Most people choose the easy way and install a MOD for the game. Hard core players use BOTH a MOD and create multiple paths if they've been drinking enough coffee to stay awake.