Help - How to build test users

Hi all,
My co-founder and I were creating a B2B SAAS application around project management to help teams collaborate, track workloads, licenses and spend. Since Covid-19 has hit we decided to pivot and promote the application to a wider audience to help with the increased numbers of remote workers, the application can now be personalised as required to separate departments i.e sales, HR or Marketing.

We're now at the point where we continue to validate the MVP and are trying to ramp up adoption and test users. We currently have two organisations using the application daily (both sub 10 users) but we need a larger install base. Can anyone provide any advice on how to market an early stage solution and how to grow daily test users?

We are bootstrapping the development and do not have a huge amount of funds for marketing.

Any help or guidance is greatly appreciated.