first when i moved an object, the object was moving in squars ( very usefull), if this setting is on, its easier to connect 2 parts to each other. i think i accidentaly changed this setting:(

so my question is: how do i activate it again?????

There are two settings, one for linear movement and one for rotations, that snap to the grid. The buttons are adjacent on the toolbar, near the left.

The hotkeys are Q (linear) and CTRL+Q (rotation) to toggle each setting. They should be reflected in the buttons in the toolbar. Pressed is on.

You can also edit the 3D position to clean up the alignment, e.g. delete all the decimal places, in the 3D tab of the edit dialog.

tnx, it is working again!