Step 8 - attaching the tailored collar
Step 8.1
Sew the collars right sides together along the 3 outer sides.
Trim the corners diagonally and turn inside out.
Step 8.2
Place it at the notch on the right side of the front, on both sides of the garment.
Stitch at 1cm and stop the seam exactly at the corner with the needle in down position. Lift the presser foot, make a small cut diagonally as close as possible to the stitch without cutting it, and rotate the fabric. Continue stitching to the other end and repeat the step at the next angle. 
Press the seam allowances open. 
Step 8.3
Turn the lapels inside out. Form neat edges and press. Take the back neck facing. Assemble it to the two pieces of the front. 
Then overlap the set and the collar, the inside edge of this set with the raw edge of the collar.
Pin, matching up the seamlines, and stitch at 1cm. Make small snips at angles as in step 8.2. Press seam allowances open and fix the collar.
Topstitch on the right side at 8mm along the edges of the lapels and the tailored collar.
Step 9 - attaching the sleeves
Overlap the two parts of the sleeve, right sides together. Pin the long edge and stitch at 1cm. Press the seam allowance towards the back sleeve and topstitch on the right side at 8mm from the seamline.
Close the sleeve.
Set the hem of the sleeves in place using slip stitches.
Pin the sleeve and armhole, right sides together, matching up the shoulder and sleeve seams. 
Stitch at 1cm all around. Topstitch on the right side at 8mm and press.
Step 10 - fixing the bottom hem
Fold over the bottom hem of the coat using the marks and press. Fold 1cm of the lapels to the wrong side at the hem and press. Turn the bottom hem over to about 2cm and hand stitch by slantingly taking one thread from the outer fabric and one thread from the fold, and so on until the whole hem is finished and fixed.
Step 11 - sewing the lining
Step 11.1
Fix the extra fabric allowance at the back with a horizontal seam at 5mm. Do the same for the front ones with vertical seams.
Sew the lining pieces right sides together. Form the shoulder and side seams. Sew the sleeves and leave an opening of about 20cm on one of the seams.
Step 11.2
Overlap the lining and the coat, aligning the edges of the lining to the inner edges of the lapels, right sides together. Fold a small part of the bottom edge of the lining to the wrong side.
Pin along the lapels and collar. Then stitch at 1cm from one end to the other.
Turn the coat to the wrong side to attach the lining to the bottom edges of the coat and sleeves. Stitch at 1cm and turn it to the right side through the sleeve opening.
Then close the opening with hand stitches. 
Step 12 - buttonholes and buttons
Mark the button holes on top of the front jacket, sew them and fix the buttons.
And here it is! Don't hesitate to share it with us :)