Seeking advice on utilizing solo 401k with a small balance

[Krista Lance]

Hi, I've just set up my Solo 401k, using funds from a previous employers retirement account. The current value is small: $12,500. I am struggling to find a way to utilize these funds in investments because the value is so small. Ideally, I want to grow they money large enough for a downpayment on a buy & hold (roughly $25-30k). I have no idea where to start or how to even find investments for such a small amount of cash.

Does anyone have any suggestions or have experience with small valued self-directed accounts?