Measure a suitable height to place the computer, create a support design as below

After contraint all sketches and before extrude, go to "Modify" > "Change Parameter"

To summarise, parameters allows edit on the extrude distance without using edit feature or extrude, which is easier to change the thickness of certain bodies or component

When extrude, instead of entering distance(thickness), enter "legwidth"(according to the name given in parameter)

After extrude, copy paste this component to same design, remember not to move the copied component.

Next, use "join" function, hide leg support 2, choose one side of the support as one reference point, unhide support 2 and hide support 1, choose oppositeface(side)

Along Z-axis distance, instead of distance entered, use defined parameter name("legdistance" in this case)

Create new component, name top(to place computer)

Create sketch on the slanted surface instead of horizontal

Use "Create > "Project include, include another face

Create rectangle and colinear to the side(so when the legsupport distance increase, this component will increase also)

Use contruction line contraint to all midpoint of rectangle

Next create rectangle(act as join), which width is colinear to the width of leg support

Mirror the small rectangle(join) using the the contruction line as reference point

Extrude inwards the rectangle other than the small rectangle(not cut but new body), distance follow("legwidth" instead distance)

Next,"modify" tool > "combine" tool

Target body is the one need to be modified, Tool body is the one to make as reference(check the keep tools so will not loose the part)

Hide the top board or tool body to see the changes made

Using the support as reference, offset plane from it using parameter or distance

Create sketch on that plan, create a rectangular and colinear contraint similar to previous steps

Sketch one line across the midpoint of rectangle

Extrude symmetric the designated sketches, except for small rectangle(join) to create the support (distance use legwidth parameter)

Next, use midplane to create a plane, use front and back plane of side support as reference

Mirror the created bottom support using midplane as reference, and modify using similar steps mentioned

Lastly fillet or chamfer the corners

Laptop Stand:

Under Design Tab, choose Animation

To move a component, select it and press transform, which is similar to move tool. Once it is move, it will be shown on the timeline where can adjust the duration

There is also auto explode which fusion 360 will automatically explode the components

When complete, there is a publish tool which can create a video of own model with animation move edited by ourself

Upload it to youtube and people are able to view your video

Own video about laptop stand