Want to add SSD storage to my computer

[Raphael1234]

I want to add SSD to my computer for more fast storage, Specs says that my computer has 2 m.2 slots but I can only find the first one that is already in use, where do I find the second one and secondly can I have SATA SSD for this motherboard, my motherboard is Moria3 

[Paul_Tikkanen]

The motherboard specs indicate that there is only support for one M.2 NVMe SSD and one M.2 Wi-Fi adapter.

HP Desktop PCs - Motherboard specifications, Moria3 | HP® Support

'Expansion slots' is a misnomer.

When you read the motherboard specs you have to assume a bare motherboard with nothing installed.

Here's an eBay listing with a picture of the Moria3 motherboard.

HP OMEN Moria3 Socket AM4 MicroATX Motherboard (GT 12, L96321-001) | eBay

It shows two SATA ports to the right of where the NVMe SSD drive goes.

What I don't see is where the SATA power cable goes on the motherboard, so you will have to find that header, unless the power cable is located on the power supply wiring harness.