I am not sure if you meant that, but for me it seems like you just want to wait 2 seconds before executing the next steps. You can do that like so:

import time

while True:
    time.sleep(2) # waits 2 seconds
    winsound.Beep(440, 1000)

Anyways I don't recommend you to use a plain infinite loop, without a break statement. Therefore I recommend you to add one, like down below.

import time

while True:
    time.sleep(2) # waits 2 seconds
    winsound.Beep(440, 1000)

    if True: # break on a specific statment
        break

Edit: As CrazyChucky mentioned in the comments, this approach should work fine in most of the cases, but it can end up being more than two seconds sometimes. Therefore you should work with timedeltas or take a look at scheduler.

while True:       # True must be upper-case!
    timer.start() # This is inside a loop so must be indented!
    ...

You'll note the error message you received tells you exactly that it needs to be indented.

Try this:

import time

t_end = time.time() + 60 * 15
while time.time() < t_end:
    # do whatever you do

This will run for 15 min x 60 s = 900 seconds.

Function time.time returns the current time in seconds since 1st Jan 1970. The value is in floating point, so you can even use it with sub-second precision. In the beginning the value t_end is calculated to be "now" + 15 minutes. The loop will run until the current time exceeds this preset ending time.