Do you want to install everything new or do you want to keep your data/OS from the HDD?
For NEW:
1. Make sure you connect the SSD to your fastest SATA port, many mainboards got main/secondary controllers for SATA. Just download your mainboard documentation, some mainboards color code them, so its pretty easy to follow the location from the pictures.
2. If you have to use another SATA port as your old one and maybe even want to keep your old HDD, you will need to change the boot device in your BIOS. Mainboard documentation helps again step by step.
For KEEPING your DATA/OS:
1. I suggest you get a free and easy backup/clone software, I used last time the free version of
https://www.macrium.com/reflectfree and the user interface was really simple.
2. You keep your old HDD where it is, you connect your new SSD to another SATA port, boot up your PC, clone your HDD onto the new SSD and if you want to replace your HDD completly you can just disconnect your HDD from the mainboard and use the same SATA port for your SSD. In this case you wont even need a fresh install nor do you need anything to change in the BIOS. This is the easiest way that many non tech savvy user prefer.
WARNING!
SSD's normally don't give you early warnings in case of a failure. You need to think about external backups of your important data.