Can I suggest that you stick with two-finger chords at the start rather than the four-finger shapes beloved of bluegrass players (and others). Think of a basic three chords for each key you play in and work round the three, getting changes smoothly and confidently.
Lets look at the key of G as an example. You would have the G major, C major and D major (or D7th) as the basic three, with an E minor if you feel a bit more adventurous! Those shapes, as 2-finger chords, would be:
G - 0032, C - 0320, D - 2002, Eminor - 0220. The numbers are the frets on the four strings, the G string being to the left in the diagrams. Practise changing between the G and C for a start, then work on other pairs as you gain dexterity.
Hope this is of help.
JK Mandolins - handcrafted in Argyll, Scotland