"To complete the installation" means to finish the process of setting up or putting in place something, typically a software program, device, or system. Full definition
In case you still have problems completing the installation of this new ROM, then you can ask for extra help at the end of this post and we will come to your aid. (android.gs)
These were all the steps that you had to take in order to complete the installation process of this new ROM on your device. (android.gs)
If you have any other questions or you can not complete the installation at your first attempt, then you should ask for more help in comments. (android.gs)