Don't think there's a B390 chipset.
And a GTX 1050 ti doesn't SLI. Other software may utilise multiple graphics card set ups.
And even if you could run multiple 1050 Tis, SLI support has gotten so lousy that there's little point in doing so. Same story with Crossfire.
I just bought 2 gpu's so I could use 4 monitors, the store that I went doesnt have gpu's that has 4 output ports so I bought to gpu to use 4 monitors. is that okay?
They mention GTX 1050 tis as examples.
Still a bit vague on the MSI motherboard. A chipset, plus CPU, may support multiple graphics cards but some of MSI's B360 motherboards don't have two full length PCIe x16 slots. You'd still need to identify which motherboard you're considering.
Also thinking whether or not integrated graphics could be enable to use the motherboard display outputs.
What CPU?I just bought 2 gpu's so I could use 4 monitors, the store that I went doesnt have gpu's that has 4 output ports so I bought to gpu to use 4 monitors. is that okay?
I wasn't sure if the OP meant two 1050 Tis or something like two 1050 Tis!
OP, it would be extremely helpful if you would be more direct and detailed with your question. What GPUs did you buy, what is your intended use for four monitors, what your exact motherboard is, what your budget is, and so on.