pay as you go. not only will you owe income taxes but also self-employment taxes. generally estimates for 2019 need to be paid 1.4 on each of these dates 4/16, 6/15, 9/15 and 1/15/2020
if you had no income the first quarter ending 3/31/19 than 50% would be due 6/15 and and 25% each 9/15 and 1/15/2020
if no income thru 5/311/19 then 75% 9/15 and 25% 1/15/2020
failure to timely pay estimated taxes will result in penalties
since you have no withholding, to avoid penalties your estimated tax payments must be 90% of 2019 tax or 100% (sometimes 110%) of 2018 tax, whichever is smaller.
TT has a website Taxcaster for estimating 2019 taxes including self employment tax
