What should I say to my next employer for why I got fired ? ?

I just got fired from a server position at a small business. They said I was fired because they can’t afford to keep me and because I was not trained properly since the server that was supposed to train me quit and with COVID they need all the business they can get. The manager who fired me said most servers last a week, and they all had a meeting yesterday to discuss my employment. They said they like me and I was improving on my skills which is why they kept me so long. The reason I’m concerned is because I’ve only been at the job since December, and because they said I needed to be trained more so I’m not sure what will be thought of me if I explain this to a future employer, and if I should even put the job on my resume.