Prerequisite: Intelligence or Wisdom of 13 or higher
You have already learned a number of spells which you able to cast them as rituals. Normally these spells were written in a particular ritual book, which you should have in your hand while casting any one of them.
However, when you select this dnd 5e Ritual Caster feat, then you can acquire a ritual book holding two 1st-level spells of your choice. You can select one of the following classes such as: bard, cleric, druid, sorcerer, warlock, or wizard. So you must need to chose all of your spells from that class’s spell’s list. Also the spell’s that you’ve chosen they must have the ritual tag. The dnd class which you select also should have the ritual tag. Of course even the class that you’ve selected also can determines your spellcasting ability for these spells such as: Charisma for bard, sorcerer, or warlock; Wisdom for cleric or druid; or Intelligence for wizard.
When you’ve come across to the spell in written form, then a magical spell scroll or else a wizard’s spellbook and you might have been capable to add it to your ritual book. Also the particular spell must be on a spell list for the class that you’ve chosen also the spell’s level could be not higher than the half your level (rounded up), and of course, it must have a ritual tag.
Basically, the procedure to copying the spell into your ritual book actually takes 120 minutes (2 hours) per a level of the specific spell and it costs 50 gp per level. This 50 gp cost represents a material components that you expend like you experiment with a spell to make it master, also the fine inks you need to be record it.