Hi, thanks for your feedback. Guide was just to show the installation and create a thread to help those who want to put up their Node. To answer your questions:
How do I set up channels?
Who do I open with?
To open a channel you need to connect with other nodes, preferably find some trusted partner (there are plenty of these on the Internet just search). Then in the Umbrel panel in the Lightning Network section you need to click Open channel and fill in the relevant information about the node with which you want to create a channel and the amount of BTC.
How much liquidity do I supply?
In general, the amount of liqudity depends on you. Ideally, it should be balanced on both sides (yours and your partner's). It should also be monitored and rebalance if necessary.
Lightning Networksection you need to clickOpen channeland fill in the relevant information about the node with which you want to create a channel and the amount of BTC.