Their website is pretty straightforward to use and spells out the grading resources and prices in an easy-to-understand way
They also have a handy app
To get access to the other two Class abilities, you will have to activate as sorcery (meaning during your main phase) to take the class to Level 2, and you can pay the cost again to take it to Level 3, but note that you will need to reach Level 2 first before you can access Level 3
Key Highlights: Authentic vintage 1st Generation Eevee Pokmon card
A vanilla two mana 2/2 is probably a 1.0 these days, and while I think triggering celebration is doable, it isnt going to happen so much that this will be a 3/3 with trample every turn or anything This is great in terms of sacrifice fodder, as it gives you two bodies for the price of 1
Necroduality is the perfect enchantment for this deck