I have 16 months between my youngest two and I also had an older son so I had 3, 3.5 and younger when dd was born.

I bought a cradle, dd slept in it until 7 months old. Ds2 stayed in a cot until 2 and was then moved straight into a bed and dd moved into the cot. Dd slept in the cradle in out room so never needed to buy a new monitor.

I carried dd until recently and just used an umbrella stroller for ds2 but it has got too hot for little miss too be carried and she is rebelling against it so I have recently bought a double pram.

Nights I find are the hardest thing with kids so young together. Ds2 was still night waking when dd was born and both still are so I am up a lot of the night. But other than that you manage. I was super overwhelmed at the thought before dd was born but it's be fine.