The forms on which you have to apply for indefinite leave to remain in the UK can be found on the GOV.uk website. This page will lead you through a series of questions about your immigration status and will tell you which form you need. The two main forms are listed below.
You can now choose an option using your keyboard (number keys or function keys). To start up in Safe Mode, press 4 or F4. To start up in Safe Mode with networking, press 5 or F5. To start up in Safe Mode with the Command Prompt, press 6 or F6. If you change your mind and decide you don't want to boot into Safe Mode after all, hit Enter to boot normally.
Choose the type of Safe Mode for your situation. Safe Mode starts the computer in the most bare-bones configuration possible; Safe Mode with Command Prompt allows you to boot up with the option to open a command prompt; and Safe Mode with Networking gives you Safe Mode, a command prompt and internet access.