Hello Scott, and welcome.
A good way to start is to begin adding what you know about your parents and then grandparents. And look at the help at the following link:
Use the ʻHelpʻ menu and ask questions here on G2G, you will find many members who will help with research and answer questions about building profiles.
You might want to use the ʻFindʻ menu and click on Surnames, then follow the instructions to search Armstrong or any other surname that interests you.
The important thing is to start, to ask for help and to not get frustrated. There is always guidance available here.