Ive done a lot of inside joint repairs were getting out the seaming iron is the biggest problem. You have to change direction at corners then at the end back up and lift while pressing on the end of the carpet over the tape often it still bunches the end of the tape. Ive also used a glue gun where you do about 6 inches then spread with a used blade so it wont seep push down then the next section the secret there is using a hotter professional glue gun so you have more working time this works on about a foot or less sized hole. Steaming Ive tried it at home and then checked they weren't strong enough. The kool glide is a game changer for blind repairs but for regular open seams there really is no advantage over a standard iron. If your new to repairs get a cool glide it will make you a pro much faster and better to start with the best blind repair method. They are a cool heat kind of like those new stoves where they only heat metal so there is metal foil in the tape.
My patch method is I use a framing square and a new square edged blade (it cuts deeper/cleaner) used carpet you cant free hand cut in corn row its warped and soft but let the carpet under the square bend down and run a screwdriver to lift the ones going the other way to lessen face fiber cutting keep blade straight down don't angle it weakens things and edge will break up. Make that your pattern and position face to backing on doner and cut on the doners backing (its easier and you wont cut face fiber and needs to be exactly the same size). lining up your square moving the pattern cutting then put pattern against the cut and line up next line. After cutting position and put the cool glide on it and call it done. So cut, use as pattern, cut doner, position and then cool glide. Patches are usually 100.00 and take about 20 minutes so its worth it and with cool glide your only issue is cutting and the square solves that issue.