A "backdoor" Roth conversion is when you make a non-deductible contribution to a traditional IRA (because you are ineligible to make a deductible contribution) and then do a Roth conversion. The Roth conversion is totally normal actually, but the non-deductible contribution changes how it counts towards your income. For the classic backdoor, you have no deductible contributions or rollovers to any traditional IRAs (of the same type I believe) owned by you. In that case the only income the Roth conversion adds is any growth that occurred between the contribution and the conversion.
If you have any deductible tIRA contributions in any other same-type tIRAs to go along with your non-deductible contribution then you have to assume that the Roth contribution is taken proportionally from all deductible and non-deductible balances in all those tIRAs. That can screw up the normal backdoor scheme because you'll owe taxes on the deductible portion of the conversion amount.
A completely normal Roth conversion is from an all-deductible-contributions tIRA. In that case the whole conversion amount adds to your income. As far as the mechanics, you can convert just some or all or your tIRA. You can transfer shares in-kind from tIRA to Roth so that your AA stays the same. You can have taxes withheld, though that reduces or eliminates the benefit of the Roth conversion and should probably be avoided. There are no more conversion recharacterizations, so your Roth conversion is permanent. You must plan for taxes either through equal quarterly estimated tax payments, or other sources of withholding, either via Safe Harbor or getting close to the amount of tax that will be due.
You might consider Roth converting early in the year (letting it grow the rest of the year tax-free in the Roth account), or several times during the year (monthly?), or at the end of the year (when your taxes can be estimated). Ideally you want to convert when your tIRA is at it's lowest value of the year so you maximize the percentage converted for the tax you pay. Of course, good luck with that!
Roth conversions are just a tax minimization. tIRAs have required minimum distributions beginning at 70.5 (currently). Look at the taxes you might pay at that time, considering the RMD as your last dollars of income. Roth accounts don't have RMDs and they reduce the amount in your tIRA, thus reducing your RMDs. That might keep you from jumping to a higher tax bracket later.
There are also the obvious tax timing considerations. If tax rates go higher in the future, it might be better to pay at today's lower rates by Roth converting. If the value of your tIRA falls by 50% in a recession, you can convert with 50% tax savings (sort of) and ride the recovery back to 100% (hopefully) in the Roth tax free. If you have no income for a few years in early retirement you might be able to get some tIRA money out at 0% or 10%, or at least lower than what RMD's will be taxed at.
Even if you will be taxed at the same rate now and for RMDs the Roth can be beneficial. A tIRA holds some of your money and some of the IRS's money. If your tax rate is a simple 15% and always stays the same, the IRS owns 15% of your tIRA. You give them some of their 15% every time you withdraw from the tIRA. With a Roth it's all your money. So $100 in a tIRA is like $85 in a Roth as far as what belongs to you. But when you convert $100 from a tIRA and put it all into a Roth, now you have $100 that's all yours. Since you paid $15 to the IRS for that conversion from your taxable account, it's like adding $15 of your taxable account money into your Roth retirement account, where it is now tax free. So regardless of any other tax timing benefits, you are now avoiding taxes on $15 that used to be taxable. The advantage of that depends on your tax situation, but worst case is that it gains you nothing if you were paying a 0% tax rate for your taxable account.