I am getting a timeout error 408 when trying to load a third-party template onto my AWS-hosted wordpress site. How do I fix this?

I'm using AWS to host my wordpress site. I have purchased Semplice 4 which is an appearance/theme that I need to manually load onto wordpress. However, every time I try and load it, I get a HTTP timeout 408 error code.

I assume this is something to do with the way my AWS, but due to my inexperience am unable to troubleshoot.

Apologies in advance for my beginner-level knowledge, but I'll try and explain what I have done via setup as best as possible.

I used EC2, then created an instance and an elastic IP (which I connected to the domain name I've purchased).

Then I was using Route 53 to create a hosted zone and that record set has my domain name attached to it as a type 'A' (as well as the stock NS and SOA). I then took all the values from the NS record set and input them to my domain provider so it would link to my domain name.

I then loaded wordpress using the WordPress Certified by Bitnami option, and then I have to upload this zip file in order to use the third party software and it's not working - I get the 408 error.

Request Timeout Server timeout waiting for the HTTP request from the client.

Is what I see, and it should just initialise the template.