Hello brothersofield,
Welcome to Communities.
"and then I was searching of how to use local shared datastore"
There is no feasible way in ESXi to share locally-attached drives for the purpose of availability - even if this was possible, how can you access the storage on a host when it has lost power/network or otherwise crashed?
"nonetheless I've read some thing regarding of VSan, but I can't understand it very well and if i would be able to set up this machine in order to share their datastore."
vSAN provides availability to the data by storing multiple replicas of the data on multiple hosts (+ Witness data to confirm which copy of the data is most current in the event of loss of a replica); e.g. in a 3-node cluster, Host1 has the 1st copy of the vmdk data, Host2 has the 2nd copy of the vmdk data and Host3 has the Witness-component - we can lose any one host here and still have a) a full copy of the data available and b) Quorum (e.g. >50% of all components available).
Unfortunately it is not just a case of enabling vSAN on the hosts - this requires its own licensing (on top of ESXi licensing), hardware components that are certified and supported for running vSAN (controller(s), cache-tier SSD(s) and capacity-tier HDD(s)/SSD(s)) and if you were going to operate with just 2 data-nodes then you would require some other infrastructure (or Cloud) to host the Witness Appliance on.
I would advise talking to your partner/hardware vendor for pricing of a 2-node (+ Witness) set-up (either ReadyNodes or Build-Your-Own) and maybe consider the pricing of this vs a small NAS (if high performance isn't a requirement).
Bob