There are 2 ways to do this. Hard and easy.

Hard way is manual!
Step 1A: Drag all pieces in one place outside or inside the board.
Screenshot: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2938257584
Step 1B: Then start building it in circle around the pile.
Screenshot: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2938258263

Easy way is using Automation!
Go to Guides section of Pixel Puzzles: Birds linked below. Choose Auto Puzzler guide by Grimagin! It details an auto script to pile puzzles pieces and automate complete puzzle. The canvas size is different here so it will not auto complete but definitely line pieces up in order and you can build it faster without punishing fingers manually start to finish. Download run Auto Hot Key [AHK], Copy script in guide in notepad, save as AHK file, run it. This script works on all standard pixel puzzles games till 350 pieces.
https://gtm.steamproxy.vip/app/344230/guides/#scrollTop=700

Step 2A: After running AHK, use mouse to zoom out and fix maximum view of puzzle board and pieces. Keep zoom out maximum. This game has flexible scrolling of canvas so avoid any across screen slide movement or screen zoom when in automation script, As it changes X and Y co-ordinates needed to pile them in one place centrally aligned. Carefully Drag mouse over pieces outside board on both sides. Click 'C' button on puzzle pieces. The pieces will snap at one place outside board. For better mapping keep board slight off center to left so pieces land outside mixed pieces on right side.
Screenshot: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2938259224

Step 2B: Once all pieces piled in one place on top of each other instead of manually dragging them to auto lock around Click Number 4 key for puzzles upto 220 pieces. Click Number 5 key for puzzles ranging from 300-600 pieces. Upto 350 pieces they will line up in order. Snap them in lined order bottom to top - right to left OR top to down - left to right. For leftover pieces still in pile after 350, use manually circling of completed chunk as outlined in Step 1B above!
Screenshot: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2938259753

Screenshot: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2938260005

Done! Do rate guide if helpful.