Timing mark diagram

Here is a guide and the diagrams below so you can see how the job is done:

https://www.2carpros.com/diagrams/kia/sephia/1997

Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed. Cheers

Timing belt
Removal
Disconnect negative battery cable. Remove all accessory drive belts. Remove generator bolts. Remove water pump pulley. Remove crankshaft pulley bolt, and remove pulley and timing belt guide plate.
Remove upper and lower timing belt covers. Rotate crankshaft clockwise until No. 1 piston is at TDC of compression stroke. Ensure camshaft sprockets and crankshaft sprocket timing marks align. See Fig. 2 and Fig. 3 . Camshaft sprocket "I" and "E" marks must face up and align with marks on rear timing belt cover.
If reusing old timing belt, mark belt with arrow to indicate original direction of rotation. Remove timing belt tensioner pulley. See Fig. 4 . Remove timing belt.
Fig. 2: Aligning Camshaft Timing Marks
Courtesy of KIA MOTORS OF AMERICA, INC.

Fig. 3: Aligning Crankshaft Timing Marks
Courtesy of KIA MOTORS OF AMERICA, INC.

Fig. 4: Timing Belt Tensioner & Idler Pulley
Courtesy of KIA MOTORS OF AMERICA, INC.

Inspection
Check timing belt for cracks, peeling, abrasion or other damage. Check tensioner and idler pulley bearings for looseness or roughness of rotation. Inspect tensioner spring for stretching. Replace parts as necessary.
NOTE:Manufacturer recommends replacing timing belt tensioner spring whenever timing belt is replaced.

Install tensioner pulley with NEW spring. Move tensioner away from timing belt, and tighten center bolt. Ensure camshaft and crankshaft timing marks are still aligned. See Fig. 2 and Fig. 3 .
Install timing belt around crankshaft sprocket. If reusing old belt, ensure belt is installed in original direction of rotation. Keeping belt pulled tight on right side (facing engine), route belt around idler pulley, camshaft sprockets, and tensioner pulley.
Loosen timing belt tensioner center bolt, and allow spring to apply tension on belt. Tighten tensioner center bolt. Rotate crankshaft clockwise 2 complete revolutions. Ensure timing marks align. If timing marks are not aligned, remove belt, realign all timing marks, and repeat installation procedure.
Check timing belt deflection with 22 lbs. (10 kg) of downward pressure applied to belt, midway between camshaft sprockets. Timing belt deflection should be .36-.45" (9.0-11 mm).
If timing belt deflection is not within specification, repeat timing belt tensioning procedure. If timing belt deflection is within specification, install timing belt covers. Install crankshaft and water pump pulleys. To complete installation, reverse removal procedure. Adjust drive belts to proper tension.

Could be a bad belt or bad tension-er or even a bad repair.