Hello,
Memory:
The Aspire R7-371T series is shipped with 4 or 8Gb onboard memory according to the motherboards and no upgradeable (no DIMM socket available).
SSD:
Yours is equipped with one M.2 2280 SSD of 256Gb. As your motherboard has two M.2 sockets, you'll able to add a 2nd SSD. The original ones are Kingston, Samsung or Lite-on.