@hela123,  Just do what the error message tells you:  Please read the section (3) marked essential in (2) in the forum topic marked [Must read]: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a) In particular the section on Avoiding common mistakes.

hi Andy, thanks for replying. Do i just add the gnd anywhere or to a particular node?

Anywhere. Just try it. Learning through play is powerful stuff and not just for kids.

Update: New Error :(

Sorry if my questions seem to trivial -- i have absolutely no knowledge and am trying to figure things out for a college project. Appreciate your help and patience.

@hela123, "i have absolutely no knowledge and am trying to figure things out for a college project." Hence our insistence that before trying to simulate a circuit, people MUST read the Simulation Tutorial. Would you climb into the cockpit of an airliner and expect to be able to fly it without reading the instruction manual? :) I think that there are a couple of mistakes in your sim schematic. You have used symbols that have no spice models associated with them; You have edited the prefixes using illegal characters that unfortunately LTspice is reading as part of the spice netlist and getting very confused by. Sooooooo, I think what you need to do is to replace each of your symbols with their equivalents from here: **Spice Symbol > Sysytem > Digital Device**:  However... "Appreciate your help and patience." Thanks and I owe you an apology because I think we have also messed up our own Digital spice symbols library. Basically you can use the symbols in the **Spice Symbol > Sysytem > Digital Device** libray but anything that has a _US or and _CN suffix has to have the name changed in the Schematic so remove the suffix. So, for example, if you place an INVEE_US symbol in the schematic, you need to double-left-click on the name to edit it to INVEE. Then hit the Enter key to enter the change. Similarly, if you place an OR3EE_CN symbol in the schematic, you need to double-left-click on the name to edit it to OR3EE. Then hit the Enter to enter the change. A bit of background. When EasyEDA started up it used the FOSS Ngspice simulator but in the last year or so it swapped onto using LTspice. Unfortunately the old Ngspice logic models are incompatible with LTspice so all the digital libraries have been rewritten from scratch and there are some mistakes in mapping the symbols onto the new models.