Okay, firstly hi and welcome to the game. Infinity is a great game to play and one that will really test your mind, so enjoy yourself
The factions in infinity are each unique in their background, theme and playstyle so for the most part figures cannot be swapped between factions. The two major exceptions are the mercenaries and some sectorial lists which allow for other factions models (such as one of the Haqquislam ones which allows a single Nomad Mobile Brigada)
For now what you have in the two starter sets roughly equates to two 150 point forces, which is all you really need to get started and really learn the rules. Ideally you want to start with two 30 point armies of three basic infantry each and then work up from there, and 150 points should be your maximum points for several games, at least until you have a firm grasp of the rules.
Once you expand there are a few basics to consider: Firstly do you want to stay vanilla or go sectorial? Either way, a copy of at least one sectorial starter set is always a good buy, as they contain a good mixture of infantry for you (usually 120 -140 points worth).
For Nomads I would start off with either the Bakunin starter set, which comes with two Moderators (cheap basic cheerleaders, which can also be your lieutenant), a Die Morlock (a good distraction and cheap frenzied unit - better with a chain rifle though), a Riot Grrrl (cheap Heavy Infantry that carries a Blitzen - anti big things cannon - and can be a Specialist Operative for the mere cost of a single point), and a Sin Eater Observant with a
HMG (an amazingly good cheerleader/
ARO piece that can lock down entire segments of the board without moving once).
Alternatively there is the Corrigedor set which contains three Wildcats (good basic infantry/cheeleaders), a Alguacile Hacker (not a bad starter hacker as she has a decent
WIP, but would be best replaced with a Tunguska Intereventor in Vanilla), a Hellcat (a good surprise unit that can perform aerial insertions), and an Intruder (a great infiltrating piece that can wreck face).
finally grab a Support box as well.
for Vanilla I would then add in a Tunguska Interventor box (THE best Hackers out of all the human factions), a Zond box (your basic remotes, capable of acting as turrets, Missile platforms, scouts/detectors and Hacker range extenders) and a Moderators box (great cheap cheerleaders). Leave a
TAG for another time, but advise the Lizard when you do - t is a good, no nonsense
TAG.
For Bakunin I would grab the Moderator box, and then get some Reverend Moiras, and a Custodier or two. The Zond Remotes are once again a must. The only
TAG Bakunin can have is the Lizard, but it is a good one to get.
Corregidor likes its punchiness - grab a Wildcat box, and some Jaguars and then get the Tomcats too, for some sweet
AD objective grabbing goodness. The Zonds are not so much of a must here - you wont be playing defensively! For
TAG's here go for the Gecko's. They are essentially buffed up Heavy Infantry and can be great cheap support units for your Infantry. Alternatively they also have access to the Iguana which is a little sturdier and ejects a Heavy Infantry with a Heavy Machinegun when it dies, which can be great, especially as he is a specialist operative.
For Pano would be cautious about the Heavy Infantry meme. Father Knight spam is only good in sectorial.
Once again grab a starter box, but choose which way you want to go. Heavy Infantry spam? Military Orders. Medium Infantry Annoyance? capetaline.
Be wary of the Cutter - a
TO TAG is nasty, but once again it can be a double edged sword.
The Tikklebang/Ulahns are both good but light TAGS - use them as either annoyance or precision weapons.
And finally:
Get. Basic. Infantry.
You can never have enough cheap order mooks.