Memory allocation

I need help to assign correct memory resources for my database

i have oracle database 12C and server specs is 16 GB Ram on linux 6.7

current configuration is :

sessions         472

processes       300

transactions    519

pga_aggregate_limit                  4G

pga_aggregate_target               2G

memory_target                          0

sga_max_size                           2256M

sga_target                                 2256M

db_cache_size                           0

i need to have session =1000

and need to know what values i should change from the above to hold a huge amount of transactions (example: 1 Million Trx per day) and do i need to change SGA or PGA or DB cache size?

also what is transaction value refer to and what value should it be?