This technical report describes the entire development process for all mathematics items and tests used in CBMSkills. A brief introduction highlights the purpose of the assessment system, noting their important relationship with easyCBM. Given the items are designed to provide teachers diagnostic information on students' specific skills within uniform domains (alternate items targeting the same skill), along with feedback to students on their correctness in item responses (and when incorrect, providing the answer that is correct as well as overall performance), these assessments are best used formatively that is integrated with instruction. Information is subsequently presented for each grade level describing the common core standards that serve as the blueprint for item development. Then the item development process is presented using various algorithms in Excel to create equivalent alternate items. After item development, a formal alignment of the CBMSkills with easyCBM is described in which the modules are formally reviewed for their potential in helping students be successful on easyCBM items with (a) adjustments made in coordinating the modules, and (b) another judge confirming/disconfirming the first alignment judgments. In the end, tables are presented on the number of easyCBM items that are sufficiently aligned so they can be used in a computer adaptive test (CAT) to place students in the CBMSkills modules for practice and feedback. The technical manual ends with an extensive set of tables placed in an appendix that present the reliability of alignment for each modules in each grade, providing teachers confidence in using CBMSkills as assessment-intervention platform for improving students' performance on easyCBM.