I just wait for baby to establish it.
I have always used bouncy chair and dummy for all downstairs naps until they extend. I'm quite vocal on this, so useful is the bouncer in extending naps.
I like EASY routine throughout the daytime until naps extend (Eat, Activity, Sleep, You time) on a 2-2.5h cycle. So this involves limiting awake time to 60-90 minutes and very regular feeds.
EASY cycles start first thing in the morning and continue right through until I go to bed. At every naptime wake-up I would initially try to re-settle baby back to sleep with gentle bounces and dummy re-insertion. Often this wasn't happening. As baby gets older, re-settling gets easier and more successful and as such baby starts sleeping through one sleep cycle and into another - marking the start of naps extending.
When you start "forcing" nap extending by consistent and effective re-settling, eventually less and less re-settling is needed until no resettling is needed for baby to stay asleep for longer (for daytime naps this is). This is how I have always got naps to extend.
So you are asking about evenings, in my view evenings and having a 'proper bedtime' is all tied into daytime naps moving from short frequent naps to fewer, longer naps.
My EASY routine would continue all day and into the evening. At anytime between 6pm and 8pm when baby was awake, I would call that 'bedtime' and do the bedtime routine (bath, massage, PJs on) but then be back downstairs with me in the bouncy chair for another EASY cycle. Therefore baby would have another short, 45 minute nap followed by a feed and some awake time. Then I'd go to bed and take baby up with me when baby was ready for next sleep - so night sleep would start, in the cot in my bedroom.
This ^ is how things are for us from newborn. When EASY routine naps start extending (for us this was around 5 months old) and I would find that I was doing 'bedtime', putting baby to sleep in bouncy chair but baby wasn't waking up again. It got to the point where I was waiting for baby to wake for a feed so that I could go up to bed (taking baby with me). Or worse, I was having to wake a sleeping baby to carry her upstairs to bed when I wanted to go to bed.
So once this point came, where baby just stopped waking up in the evening, that's when I decided to start settling baby to sleep in the cot upstairs at 'bedtime', as part of bedtime routine. I wouldn't have bothered with separate bedtime for baby if it meant I was up and down the stairs all night re-settling. I value my evenings too much!