I am new to rooting and custom recoveries, so please be gentle.

I've been rooted for a while now and using some apps with root access and I'm quite happy with it.
So I'm ready for the next step, installing my first custom recovery.
With flashify and the method hereunder, I think I managed to get TWRP installed.
If I now look in flashify, TWRP 2.6.3.2 shows up as current recovery for backup, so I guess TWRP installed succesfully.
My next step would be to make a full backup I guess.
But how do I "open" or get "into" TWRP, do I have to use a key combination or something while rebooting?
It's probably a stupid question but if anyone can clarify I'd appreciate it.