"I will walk and you will run."
Translation:jIyIt 'ej bIqet.
If you have a screen shot or at least tell us what you entered, it would be helpful. However, in this case, I am confident I know where the problem lies. You are probably using lowercase L to write jIyIt and bIqet. However, there is no L in either of those words. All of those upright letters are the vowel i, capitalized. The letter i is always capitalized in Klingon and with sans-serif fonts, like the ones that Duolingo uses, it can't make it difficult to distinguish l and I. But look back at those letters and see if you can't see the small curl at the bottom of the lowercase L which is absent from the uppercase i.
An explanation is given in the Tips & Notes, but I know it’s a lot of new information and some details are bound to be difficult to understand or slip through the memory. However, since Duolingo has hidden the Tips & Notes I want to make sure you know about them and where to find them. If you have not been reading the Tips & Notes, I would like to ask that you review those.
If you are doing the course on iOS or Android, you cannot currently access the Tips & Notes through the app. To access the Tips & Notes, you will have to access the course using a web browser at https://www.duolingo.com/. You can still do it on your mobile device, but you will have to use the web browser instead of the app (or you can do it from a computer). When you click on a Skill, it will expand to reveal a large Start button, a small key button, and a large Tips button.
If you click on the Tips button it will reveal the Tips & Notes and give you a detailed explanation of the grammar that is introduced in that Skill. If you have questions after reading the Tips & Notes for any Skills, we are happy to answer your questions, but many of your questions will probably already be answered in the Tips & Notes.
'ej conjoins sentences (or really any verbal clauses). It comes between the penultimate and final verb sentence being conjoined.
je conjoins nouns (or noun phrases). It comes after all the nouns being conjoined.
(There's also an adverbial je that comes after the verb is modifies; it means also. For example, Duj vIlegh je I also see the ship. This is identical in form to the noun conjunction je. Don't get them confused.)
pIj maSuvpu' batlh maSuvpu' 'ej maQapbejta'
In our many battles, we have fought with honor and achieved... victory!
Qu' buSHa'chugh SuvwI', batlhHa' vangchugh, qoj matlhHa'chugh, pagh ghaH SuvwI''e'.
If a warrior ignores duty, acts dishonorably, or is disloyal, he is nothing.
I make the assumption, quite justified I believe, that 'ej, qoj, and pagh all work the same way.
This is explained in the Tips and Notes.
After choosing a lesson unit, instead of clicking on Start, click on the little lightbulb icon next to it instead -- that will take you to the Tips and Notes. After reading them, you can then start learning that unit by choosing the Start button at the top of the Tips and Notes page.
Joining two nouns is explained in the Tips and Notes for the first unit, https://www.duolingo.com/skill/kl/Useful-phrases/tips-and-notes (section Joining nouns with and without "and"), and joining two sentences is explained in the Tips and Notes for the first unit on the second row, https://www.duolingo.com/skill/kl/Sentences-1/tips-and-notes (section Joining two sentences with "and").
If something is still unclear to you after reading the Tips and Notes, please ask specifically.
If you feel you have understood the difference, I suggest you try creating a couple of phrases or sentences here for practice. (For example, how would you say "Torg and Mara walked" or "Torg jumped and Mara ran"?)