Hi Suganthi,
I can give you a start, some pro users can suggest you better.
1. Don't use this much of connections on a single postgres server. Use a connection pooler in front of it.
2. RAM: Depends upon how much data you want to be cached.
3. Use PCIe SATA SSD with RAID10, Postgres uses a lot of IO for its operations.
Happy to help :)
Prince Pathria Systems Architect Intern Evive +91 9478670472 goevive.com
There's no such thing as PCIe SATA, use PCIe or NVMe in RAID-10, it's quite affordable these days and meaningless not to use.